Gemini CLI's autonomous tool loop silently consumed 47 million tokens on a five-file refactor

A developer using Gemini CLI with a paid Vertex AI API key asked it to refactor a few test files. The CLI's default autonomous agent mode ran a reason-act-observe loop, calling ReadFile and Shell tools to gather context and re-sending the entire growing history on every request. The session logged 251 requests consuming 47,185,013 input tokens on gemini-2.5-pro - which the reporter priced at roughly $940 at a conservative $20 per million tokens. When the account hit its tokens-per-minute limit, the CLI displayed a misleading error about the AI Studio free daily quota, masking the real problem. A follow-up session consumed another 721,943 input tokens in under 14 minutes of wall time.

What this means for youIf you use an AI coding tool on a paid API key, a single task can silently run up a large bill. At work, teams should set spending caps and usage alerts before letting agents run unattended.